ditto what dannyboy said. people who want to go out all the time do go out all the time, but there aren't so many of them at LSE.
if you're doing single honours philosophy then in many ways UCL is the better option. take a look at the undergrad courses offered by LSE; there aren't very many, and a good number fall under the philosophy of science and social science, and formal logic. there's nothing wrong with that per se, but your interests may lie elsewhere. i'm a current philosophy and economics student at LSE, but at the moment I can't vouch for the quality of teaching as I'm only doing the introductory first year course. it's a very general overview of the subject, so in that sense doesn't tell you much about the higher level courses.
try not to let the prestige factor affect your decision too much. in terms of employment opportunities, i think the difference between an lse and a ucl degree will be minimal.